Program for Recursive Topological Sorting

from collections import defaultdict

class Graph:

def __init__(self,vertices):

self.graph = defaultdict(list) 

self.V = vertices 

def addEdge(self,u,v):

self.graph[u].append(v)

def topologicalSortUtil(self,v,visited,stack):

visited[v] = True

for i in self.graph[v]:

if visited[i] == False:

self.topologicalSortUtil(i,visited,stack)

stack.insert(0,v)

def topologicalSort(self):

visited = [False]*self.V

stack =[]

for i in range(self.V):

if visited[i] == False:

self.topologicalSortUtil(i,visited,stack)

print (stack)

g= Graph(6)

g.addEdge(5, 2);

g.addEdge(5, 0);

g.addEdge(4, 0);

g.addEdge(4, 1);

g.addEdge(2, 3);

g.addEdge(3, 1);

print ("Following is a Topological Sort of the given graph")

g.topologicalSort()